Intracranial Aneurysm

All large aneurisms need to be treated to prevent a type of stroke called a subarachnoid hemorrhage. However, some smaller aneurysms can be difficult to treat. Deciding to treat is based on the size. I normally counsel on the risk of rupture based in the ISUAI study. The rate of subarachnoid hemorrhage with aneurysms in internal carotid artery, anterior communicating, anterior cerebral artery, or middle cerebral artery were 0%, 2. 6%, 14 5%, and 40% for aneurysms less than 7 mm, 7-12 mm, 13-24 mm, and 25 mm or greater. The rate of subarachnoid hemorrhage with aneurysm involving posterior circulation and posterior communicating were 2 5%, 14 5%, 18 4%, and 50% for aneurysms less than 7 mm, 7-12 mm, 13-24 mm, and 25 mm or greater.

There are no guarantees of rupture and this data just represents some of the historical experience when aneurysms are followed over time without treatment. The rate of rupture if people get surgical closure is much, much lower but there are risks from surgery. Aneurysms can grow over time and that it is reasonable to follow them over time to make sure they are not growing - since larger aneurisms have more risks. MR Angiograms and CT Angiograms are used to re-check them.